Nanofibers may help speed healing after heart attacks, preventing heart failure and improving quality of life, a study on rats and pigs suggests. Scientists injected lattices made of the minuscule fibers alongside varying doses of a growth molecule called VEGF into animals’ heart tissue immediately after induced heart attacks. The fibers protected the growth treatment, helping the tissues to regenerate arteries and improving heart function almost a month later without harmful side effects, according to the study published today in the journal Science Translational Medicine.